The Role of Marsh-Derived Macrodetritus to the Food Webs of Juvenile Chinook Salmon in a Large Altered Estuary

• Published in: Estuaries and coasts Vol. 32; no. 5; pp. 984 - 998
• Main Authors: Maier, Greer O., Simenstad, Charles A.
• Format: Journal Article
• Language: English
• Published: New York Spring Science + Business Media 01-09-2009; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Anthropogenic factors; Aquatic ecosystems; Biological and medical sciences; Brackish; Brackish water ecosystems; Coastal Sciences; Detritus; Earth and Environmental Science; Ecology; Environment; Environmental Management; Estuaries; Fisheries science; Food chains; Food quality; Food webs; Freshwater & Marine Ecology; Freshwater fishes; Fundamental and applied biological sciences. Psychology; Isotopes; Marine fishes; Marshes; Oncorhynchus tshawytscha; Organic matter; Phytoplankton; Rivers; Salmon; Stable isotopes; Synecology; Vascular plants; Water and Health; Wetlands; Young animals; INE, USA, Columbia Estuary; Juvenile Chinook; Food webs; Isotopes; Detritus; Columbia River estuary; Brackish water environment; Vertebrata; Oncorhynchus tshawytscha; Food web; Pisces; Estuaries; Marsh; Young animal
• ISSN: 1559-2723; 1559-2731
• DOI: 10.1007/s12237-009-9197-1

The goal of this study was to determine the food web pathways supporting juvenile Chinook (Oncorhynchus tshawytscha) salmon in the Columbia River estuary through multiple stable isotope analysis (δ¹³ C,δ¹⁵ N,δ³⁴ S). Using this method, we distinguished the role of various organic matter sources in Chinook food webs and interpreted the dynamics of their use both spatially and temporally within the estuary. Our results indicate that subyearling Chinook are associated with fluvial, anthropogenic, estuarine, and marine organic matter sources, with hatchery food and vascular plant detritus being the most dominant sources in juvenile Chinook food webs. Although freshwater phytoplankton is involved in many food web pathways to subyearling Chinook, increased phytoplankton production from the impounded river has not replaced the loss of autochthonous marsh production to fish. Our results indicate that large-scale ecosystem alteration may have decreased the availability and quality of food webs in the estuary and potentially diminished the ability of the Columbia to support Chinook salmon.